1. Field of the Invention
The present invention relates generally to floor pumps and, more particularly, to a floor pump with a stable base.
2. Description of the Related Art
There are two categories of floor pumps: one floor pump is with a collapsible tripod attached on a base member, and the other floor pump is with an enlarged base member which is adapted for standing on the ground to be stepped on by users.
Referring to Taiwan Patent No M278776, a floor pump includes a cylinder 11, a piston linkage 12, a channel 13 and a joint 14. An end of the cylinder 11 is closed and stands on the ground. A tripod 15 is attached to the end of the cylinder 11 and formed by a bent metal. In an operative position of the pump, the tripod 15 is expanded to abut against the ground. The tripod 15 is folded to attach to the cylinder 11 while the pump is in a storage position. The tripod 15 is able to pivot with respect to the cylinder 11 so that the pump is easy for switching between the storage position and the operative position. However, while pumping, the tripod 15 can not provide a stable support, because the cylinder 11 might swing with respect to the tripod 15.
Referring to Taiwan Patent No M260634, another floor pump includes a base member 11, a cylinder 12, a hose 13 and a piston linkage 14. The cylinder 12 and the hose 13 are coupled to the base member 11. However, an abrasion phenomenon of a connector between the base member 11 and the cylinder 12 is going to occur when the piston linkage 14 is moved in the cylinder 12 up and down over a long period of time. In operation, users step on the base member 11 and operate the piston linkage 14 to pump air into the pump upward and to pump air out of the pump downward. As the piston linkage 14 is moved upward, a piston connected to the piston linkage 14 rubs against the cylinder 12 to provide an upward force to the cylinder 12, while users standing on the base member 11 provides a downward force to the base member 11. Therefore, the connector between the base member 11 and the cylinder 12 bears the upward force and the downward force at the same time. The larger the strength users put forth, the larger torque the connector bears. It might cause the cylinder 12 to break easily. In addition, the cylinder 12 is straight, so that the structure strength of the connector is weakened.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in the prior art.